The term "polyphenylene ether resin" is descriptive of a well known group of polymers that may be made by a variety of catalytic and non-catalytic processes. By way of illustration, certain of the polyphenylene ethers are disclosed in Hay, U.S. Pat. Nos. 3,306,874 and 3,306,875, and in Stamatoff, 3,257,357 and 3,257,358. In the Hay patents, the polyphenylene ethers are prepared by an oxidative coupling reaction comprising passing an oxygen-containing gas through a reaction solution of a phenol and a metal-amine complex catalyst. Other disclosures relating to processes for preparing polyphenylene ethers are found in Fox, U.S. Pat. No. 3,356,761; Sumitomo, U.K. Pat. No. 1,291,609; Bussink et al, U.S. Pat. Nos. 3,337,499; Blanchard et al, 3,219,626; Laakso et al, 3,342,892; Borman, 3,344,166; Hori et al, 3,384,619; Faurote et al, 3,440,217; and disclosures relating to metal based catalysts which do not include amines are known from patents such as Wieden et al, U.S. Pat. No. 3,442,885 (copper-amidines); Nakashio et al, U.S. Pat. No. 3,573,257 (Metal alcoholate or phenolate); Kobayashi et al, U.S. Pat. No. 3,455,880 (cobalt chelates); and the like. In the Stamatoff patents, the polyphenylene ethers are produced by reacting the corresponding phenolate ion with an initiator, such as peroxy acid salt, an acid peroxide, a hypophalite, and the like, in the presence of a complexing agent. Disclosures relating to non-catalytic processes, such as oxidation with lead dioxide, silver oxide, etc., are described in Price et al, U.S. Pat. No. 3,382,212. All of the above-mentioned disclosures are incorporated herein by reference.
Cizek, U.S. Pat. No. 3,383,435 describes compositions of polyphenylene ether resins and styrene resins, including rubber modified high impact styrene resins.
The rubber modified-high impact polystyrenes, that were described by the Cizek specification, have rubber particles that have a composite structure, with an outer shell of rubber enclosing polyhedral occlusions of polystyrene that are separated by a thin rubber membrane. These are called "salami" or "cellular" particles.
A different type of rubber modified polystyrene has been described by Kruse, U.S. Pat. No. 4,097,549 and in Die Angewandte Makromolekulare Chemie 58/59 1977 pp. 175-198 which are incorporated by reference. These rubber modified polystyrenes have the rubber moiety structured on different morphological forms comprising ordinary cellular forms, bundles of rubber fibers, rubber sheets and mixtures thereof. It has been found that when this type of improved rubber modified polystyrene is combined with a polyphenylene ether resin, the resulting compositions have equal or slightly higher impact strength than analogous compositions that are made with ordinary rubber modified high impact polystyrene having a higher content of rubber. This is quite surprising in view of the fact that the impact strength of the improved rubber modified polystyrene is inferior to the impact strength of the ordinary rubber modified high impact polystyrene. The polyphenylene ether composition that contain the improved rubber modified polystyrene also have higher distortion temperatures and better gloss. It has also been found that equivalent gloss can be obtained in a polyphenylene ether composition containing the improved rubber modified polystyrene as compared to a polyphenylene ether composition containing ordinary rubber modified polystyrene, at molding temperatures that are lower by approximately 25.degree. F.
Accordingly, it is an object of this invention to provide a polyphenylene ether resin-alkenyl aromatic resin composition that has improved properties as compared to the prior art compositions.
It is also an object of this invention to provide a composition of a polyphenylene ether and an alkenyl aromatic resin that may be molded at lower temperatures.